OBJECTIVES: To investigate the effect of pachymic acid on brown/beige adipocyte differentiation and lipid metabolism in preadipocytes. METHODS: 3T3-L1 MBX cells were induced to differentiate into beige adipocytes using a brown cocktail method. The impact of pachymic acid on the viability of 3T3-L1 MBX cells was evaluated using the CCK-8 assay. The formation of lipid droplets following treatment with pachymic acid was observed by oil red O staining. The mRNA expression levels of key browning genes, including uncoupling protein (Ucp) 1, the peroxisome proliferator activated receptor-γ coactivator (Pgc)-1α, and the PR domain-containing protein 16 (Prdm16), as well as the mRNA expression of sterol regulatory element-binding protein (Srebp) 1c, acetyl-coA carboxylase (Acc), fatty acid synthase (Fas), and hormone-sensitive triglyceride lipase (Hsl), adipose triglyceride lipase (Atgl), and carnitine palmitoyltransferase (Cpt) 1 were detected by quantitative reverse transcription polymerase chain reaction. The protein expression of Ucp1, Pgc-1a, and Prdm16 was detected by Western blotting. RESULTS: The 3T3-L1 MBX cells were induced in vitro to form beige adipocytes with high expression of key browning genes(Ucp1, Pgc-1α, and Prdm16), and beige adipose-marker genes (Cd137, Tbx1, and Tmem26). Concentrations range of 0-80 μmol/L pachymic acid were non-cytotoxic to 3T3-L1 MBX cells. Pachymic acid treatment significantly inhibited the differentiation of 3T3-L1 MBX cells, resulting in a notable decrease in lipid accumulation. There was a marked increase in the expression of key browning genes and their proteins products, such as Ucp1, Pgc-1α, and Prdm16, while the expressions of fat synthesis-related genes Srebp1c, Acc and Fas were significantly decreased (all P<0.05). The expressions of lipolysis-related genes (Hsl, Atgl, and Cpt1) were significantly increased (all P<0.05). Treatment with 20 μmol/L pachymic acid showed the most pronounced effect. CONCLUSIONS Pachymic acid can inhibit fat synthesis and promote lipid decomposition by regulating the brown formation and lipid differentiation of preadipocytes.
Animals ; Lipid Metabolism/drug effects* ; Mice ; Cell Differentiation/drug effects* ; Adipocytes, Beige/drug effects* ; 3T3-L1 Cells ; Adipocytes, Brown/drug effects* ; Triterpenes/pharmacology* ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; Uncoupling Protein 1 ; Sterol Regulatory Element Binding Protein 1/metabolism*

The induction of brown-like adipocyte development in white adipose tissue (WAT) confers numerous metabolic benefits by decreasing adiposity and increasing energy expenditure. Therefore, WAT browning has gained considerable attention for its potential to reverse obesity and its associated co-morbidities. However, this perspective has been tainted by recent studies identifying the detrimental effects of inducing WAT browning. This review aims to highlight the adverse outcomes of both overactive and underactive browning activity, the harmful side effects of browning agents, as well as the molecular brake-switch system that has been proposed to regulate this process. Developing novel strategies that both sustain the metabolic improvements of WAT browning and attenuate the related adverse side effects is therefore essential for unlocking the therapeutic potential of browning agents in the treatment of metabolic diseases.
Adipocytes, Beige ; cytology ; Adipose Tissue, Brown ; cytology ; metabolism ; Adipose Tissue, White ; cytology ; Aging ; metabolism ; Animals ; Humans